Air spraying device



June 4, 1946.

J. A. PAASCHE AIR SPRAYING DEVICE Filed April 22, 1943 x xmw WWW/4 w M 0P #w J M 3 7 U M 3 a r a w 41 1% W M 5 4 W L I w 0 W M 6 W W m r fl w 5m a H7 3 aw .3 a 4 T H h 3 Z y m E. 5%.

Patented June 4, 1946 UNITED STATES PATENT OFFICE r 2,401,503

AIR SPRAYING D'EvioE J ens A. Paasche, Chicago, 11]. Application April22, 1943, Serial No. 484,039

The present invention is particularly concerned with improvements invalve'controlling mechanisms employed to govern the volume of liquidsuch as paint to be applied to a work surface in the form of a spray. Ithas heretofore been the practice in some instances, as shown in myearlier Patent No. 2,059,706, to control the delivery of liquid such aspaint by a piston operated valve mechanism. Such mechanisms have certainfunctional deficiencies which the present invention seeks to overcome.For example, piston operated valve mechanisms are subject towear andconsequent leakage. Also such devices require continuous lubrication.The present in- 've'ntion contemplates a spray device in which valvecontrol may be obtained by mechanism which is not subject to the wearexperienced by a piston and which need not be lubricated.

More specifically, the present invention con templates an improvement inthe bellows of that type of spraying device in which a liquid controlvalve may be shifted in response to the expan sion of a pressureresponsive means such as a bellows which is connected with the air line.

The foregoing and other objects and advantages will be more apparentfrom the "following detailed description when considered in conn'ec- Xtion with the accompanying drawing, wherein- Fig. l is a centrallongitudinal sectional view of a spraying device which is representative'of one embodiment of the present invention;

Fig. 2 is an end elevational view or the device,

said view being taken from the left ofFig. 1 substantially along theline 2-2 thereof;

Fig. 3 is a transverse sectional view taken substantially along the line3-3 of Fig. 1;

Fig. 4 is a transverse sectional view taken substantially along the line4-4 of Fig. 1'; and

Fig. 5 is a transverse sectional view takensubstantially along the line5-5 of Fig. 1.

Referring now to the drawing more indetail 1" wherein like numerals havebeen employed to designate similar parts throughout the various figures,it will be seen that one embodiment of the present invention constitutesa spraying device which is designated gene-rally 'by the numeral In.This device Ill comprises a forward portion or nozzle assembly generallydesignated by the numeral I 2, a central body portion I 4 which carriesthe nozzle assembly l2 'and a rearwardly positioned bellows supportingstructure designated generally by the numerallii. The f bellowssupporting structure is includes a cylindrical casing or housing I 8which is clo'sed at its rear or right extremity, Fig. 1. by a closuremember 20. The opposite extremity of the housing I8 2 is reduced andinternally threaded to receive a bearing member 22. This bearing member22 has a conical outer bearing surface which is complementary to aconical bearing surface on the body l4, and these two :bearing surfacesare secured against each other through the agency of a coupling hut '24,Fig. 1. This nut 24 makes a threaded engagement with the periphery ofthe right extremity of the body l4 and is provided with a flange portion24a which bears against a shoulder on the bearing member 22.

Liquid such as paint is introduced to the front extremity of the sprayerdevice l0 through a suitable conduit 26 which is coupledat 28 with anipple 30 formed integral with and extending outwardly from thecentralbody portion H. The fluid or liquid passes through a channel 32and thence into a chamber or passage 34 withina nozzle tip 36 whichforms 'a part of the nozzle assembly l2. The communication between thispassage 34 and a restricted discharge orifice 38 is controlled byaneedle valve member 40. The degree to which the valve member 40 is openwill determine the amount of paint discharged in a small stream throughthe discharge orifice 38. The valve member 40 forms a part of anelongated valve stem 42 which is coupled at its opposite or rightextremity, Fig. 1, with a pressure responsive bellows mechanismdesignated generallyby the numeral 44, later to be described. It will beseen that the nozzle tip 36 makes threaded engagement with the left orouter extremity of the central body portion M and is provided with anouter tapered surface foruaccommoda'ting an air can or fanning head 46.v The stream of paint discharged from the orifice 38 is acted upon byfluid or air streams from discharge ports [8 and this causes the solidmaterial stream issuing from the orifice 38 to be transformed into anatomized stream comprised of small particles of substantially uniformsize delivered against the surface to be treated. For a more detaileddescription of the fanning efiect produced by such ports, reference ismade to my Patent No. 2,l39,1 33, dated December 6, 1938.

For aclear understanding of the present invention it will suflice to saythat fluidor air under pressure is introduced through a conduit '50which is co upled with a nipple 52 formed integral with and extendingradiallyof the housin I6.

pressure right extremity. of the v at the opposite extremity with therestricted disserves to initiate breaking up the material stream i andto carry the material toward the surface of E the body to be treated inthe form of a head spray of substantially round pattern circumscribing.

only a relatively small area. .The air streams is-. suing from the ports48 cooperate with'the air streams from the annular port 66 to producethe desired spreading or farming of the material directed to the worksurface. y

The volume of air issuing from the ports 48 is controlledby a valvemember 68.. This valve member 88 is mounted within a-nipple. or ahousing It formed integral. withthe. central body portion M. Theouterextremity of the valve mem ber 68 is connected with a knob I2vwhichmaybe manually, rotated to control the space between the-valvemember 68 and its complementary valve seat. 68 serves to preventinadvertent adjustment thereof and also to retain andcompress packing Acoiled spring M surrounding the valve material 15 in place.-. Thisprevents leakageof air along the stem of the valve member 68. A passage16 establishes communication between the valve '68 and one'of thelongitudinal passages Ell. When the valve 68 is open,jcommunication isestablishedbetween. this passage 18 and the restricted discharge portsd3... ICAt this point it shouldbe understood that the farming head 46isclamped againstthe left extremity of the central body portion Mthroughthe agencyof a suitable clampijng ring 18 which is provided withknurlings or protuberances Sii'along its outer surface to facilitatemanual adjustment thereof.

From the foregoing description it will be apparent that in order fOrmaterial such as paint to be discharged through the orifice 38 the valve40 must be open. This valve is normally closed when not in use. However,as soon as air under is ,introduced through the conduit andinto thecentral chamber expansion of a benow BZ'taKes piece; Theirightextremity, Fig. 1, offthisbellows 8 2 is connected tothe valve stem byaCouplingt. I v interposed between the coupling 84 and the. closure orcap 20. This coupling! includes a member 89 having a peripheral portionprojecting beyond the bellows which is hexagonal and an inner portion 9y and provides a support for the valve stem 42. The 'alve' stem 42 isthreaded to receive a member 93' whichprovi'des a seat for theleftextremityoft the coiled pring 86 and A coiled spring 86 iswhic'hprojectsf within the bellows which is, adapted to be slidhbly,Iiested within a complementary recess provided in the member 89. Thprovides a very simple structure 'to fafcilitate removal of the valvestem without disturbingthe bellows proper Thus when the bel lows '82expands to the right, this exparisiontakes place against thecoiled-spring'86. The extentto which the valve flll'will open willbe'dependent upon the pressure exerted against the bellows 82.

A coiled spring 81 surrounding thejvalve stem 42 servesto retam'packingrings at oppositeextremities thereof position. The action of the spring81 is such as to compress the packing pothe bellows 82 anditsassociatedparts, instantaneous opening of the valve 48 is accomplished.

ment, eliminates the necessity of lubricating the positive action andparts to insure sensitive and also eliminates wear resulting fromfriction. The

pressure exerted by. the spring 86 and conse- .quently theresponsiveness of the bellows 82 to variations in pressure may becontrolled by a manually adjustable screw member 88.

This screw member 88 makes a threaded engagement with the cap 28.Rotation of the screw member in a clockwise direction, as viewed fromthe right, causes it to move inwardlyand. thus subject the coiled spring86 to increased compression. In this manner the opening of the valvemember 40 in responseto variousair pressures may be controlled. Asuitable disc '90 is secured upon the cap 20 by. anut 92. This disc 90may be suitably graduated to indicatev various pressure settings for thescrew 88. A pointer member 94 carried by the screw 88 serves todesignate the pressure setting as indicated upon the disc 90. I

From the foregoing it will be apparent that the present inventioncontemplates a sprayor airbrush device of improvedpracticalconstruction. The control of material or paint delivered to;the restricted dischargeorifice by the use of the pres sure responsive.bellows 'mechanism previously described represents a distinctadvancement over prior devices with, which I am familiar. By employingthe pressure responsive bellows arrange: ment positive opening of thevalve is assured with improved sensitivity. The simplicity of thebellows control arrangement enables it to be economically produced, andthe elimination of shiftable plung'ers, pistons or the like, requiringconstant lubrication and encountering considerable wear, makes forefliciency in operation. Also the practical arrangement of th'evalvemechanism for controlling deliveryof air'under pressure to the fanninghead represents a 'distinct. improvement over controlspreviouslyemployed. I

Obviously the invention is not limited to the specific structural.details disclosed herein but contemplates other modifications andchanges without departin from the spirit and scope of theappendedclaims.

The invention is hereby claimed as follows:

1. Aspraying device, including in combination 'nozzlemeans forsupplyingliquid to be sprayed to said nozzle, a valve for controllingthe flow of said liduid means for supplying a gas under pressure tosaidnozzle, a Sylphon bellows, a bushing carried by said bellows, said valvehaving a stem slidably housed in said bushing, said stem having a {beingpositioned on said seat,a spring in contact with fsaid'head and biasedto urgethe head to its seat in the bushing; and means providingcombetween said gas supplying means and the interior of said Sylphonbellows. v

Q 2. A spraying deviceas in claim Lincluding in combinations; housing,said bellows being'positioned in' said housing, and meansfor removablysecuring said nozzle to saidhousing. f

A spraying device as in claim 1, including in combination means foradjusting the bias of said JENS A. PAAscrin" head, a seat formed on saidbushing saicl head

